Conventionally, a hybrid laser processing apparatus including a processing head having a jet hole, liquid supply means for supplying the processing head with a high-pressure liquid, and a laser oscillator that oscillates a laser beam, the apparatus performing processing on a workpiece by jetting the liquid supplied from the liquid supply means from the jet hole to the outside in the form of a liquid column and guiding the laser beam to the liquid column has been known. (Patent Document 1)
In such a hybrid laser processing apparatus, in order to guide the laser beam in a liquid column to a workpiece, it is necessary to bring the jetted liquid column to the workpiece in a stable condition without diffusion, and also, there has been the demand to make the diameter of the jetted liquid column as small as possible from the viewpoint of yield enhancement, etc.
Patent Document 1: National Publication of International Patent Application No. 10-500903